Objective: This study compares the subjective feelings induced by aprazolam with an objective marker, changes in regional cerebral blood volume (rCBV) as measured by fast Magnetic Resonance Imaging (fMRI) and tests the hypothesis that the decrease in rCBV in the right frontal lobe and right caudate is inversely related to the degree of euphoria reported by the subjects. Method: This is a double blind, placebo controlled protocol which will compare the response of 18-24 year old adult children of alcoholics (ACOAs) and normal controls to themselves and to each other. Results: In our study of ACOAs the left frontal rCBV change correlated inversely with the magnitude of the drug response (r=-0.89, p<0.007). Conclusion: fMRI can be used to detect changes in brian function which correlate with the subjective experiences of the subjects.